The California Highway Patrol's commercial-vehicle unit is investigating whether a mechanical problem caused an accident last week on the Clavey River Bridge that killed a truck driver.
Tyler Wilson, 26, of Manteca, died about 10:30 a.m. Friday when his 1989 International semi plummeted roughly 150 feet off the bridge on Cottonwood Road, while hauling rice straw for a Rim Fire-related project in the Stanislaus National Forest.
Witnesses told CHP officers the truck's brakes were smoking before it went off the bridge. Officer Nick Norton said the team of investigators is currently examining the truck, while other officers are following up at the scene.
It was one of two accidents in four days involving Rim Fire trucks hauling rice straw for Gigli Hay Inc., a Lathrop-based company under contract with the U.S. Forest Service to provide the materials for the Burned Area Emergency Response team's aerial mulching operations.
The other, non-injury accident involved a 2005 Freightliner that tipped over Monday morning on Forest Road 3N01 near Cherry Lake Road. That truck was towed from the scene.
U.S. Forest Service personnel have "increased communication" with the contractor since the accidents, according to Stanislaus National Forest spokeswoman Veronica Garcia.
She said mulching resumed as normal on Tuesday and was expected to continue until the project is done. The BAER team originally aimed to be finished with work by Thanksgiving, but Garcia said it may take longer.
The project involves dropping rice straw from helicopters over about 4,000 acres of land that was burned in the 402-square-mile Rim Fire earlier this year.
The 1-inch layer of straw is designed to protect fire-damaged soils from rain and snow during winter storms and hopefully prevent erosion that can lead to catastrophic landslides.